Introduction

At present, there are three developmental pathways for colorectal cancers, namely, the adenoma-carcinoma sequence, serrated pathway, and de novo pathway. The adenomatous route of colorectal cancer carcinogenesis has been extensively reviewed in the literature. Conversely, the de novo pathway, which leads depressed type polyps to colorectal cancer, lacking an adenomatous phase, recently has garnered increasing attention. Research has indicated that nonpolypoid lesions demonstrate a greater potential for malignancy, underscoring the need for their early detection. This study aims to explore the endoscopic characteristics of depressed type colorectal neoplasms by using magnifying endoscopy (pit pattern classification) and endocytoscopy (EC classification). Both the structural and cellular atypias can be observed in vivo, thus enabling more comprehensive evaluation of the disease.

Aims & Methods

A total of 40719 colorectal neoplasms resected endoscopically or surgically in our institution from April 2001 to June 2022 were subject of this study. Advanced cancers were excluded. Of these, 1463 lesions were submucosally invasive (T1) carcinomas, 6839 lesions were high-grade dysplasia and 32417 lesions were characterized as low-grade dysplasia. Morphologically, they were divided into 3 types: depressed, flat and protruded type comprising 1.2%, 42.9% and 55.9%, respectively. Specifically, the distinctive features of depressed type neoplasms concerning its pit pattern and EC classification were examined.

Results

Most of the flat (93.3%) and protruded type (94.7%) lesions showed type III _L or IV pit pattern, which are common findings in adenomas.On the other hand, most of the depressed type lesions(92.4%) classified by type III s, V _I or V _N pit patterns, are typically seen in carcinomas. As for endocytoscopy, most of the flat and protruded type lesions were identified as EC2 corresponding to adenomas. In contrast, a relatively high rate of depressed type lesions was categorized as EC3a (40.0%) and EC3b (52.0%), consistent with invasive carcinomas. The proportion of T1 carcinomas in depressed type lesions was 61.3%, whereas in the flat and protruded type lesions it was 2.9% and 2.9%, respectively. Also, 10% of lesions less than 5mm in diameter were depressed, 0.01% were flat and 0% were protruded.

Conclusion

This investigation has revealed that depressed lesions can be classified in magnifying endoscopy as type III s, V I or V N pit patterns, and as types EC3a or EC3b in endocytoscopy. Lesions that have these features or these pit patterns also have a propensity to invade the submucosal layer even when they are small in size. Despite their elevated malignant potential, depressed type lesions are frequently disregarded, underscoring the critical importance of recognizing their distinctive features and accurately diagnosing lesions based on their morphology, pit pattern, and EC classification.

Disclosure

None.

Introduction

While residual subcutaneous IFX levels are found significantly higher compared with IFX IV levels, the relationships between IFX SC levels and the depth of remission in IBD remain elusive.

Aims & Methods

All consecutive IBD patients treated with sc IFX 120mg/2weeks for at least 8 weeks were included in a multicenter study. All patients were switched from iv to sc IFX at least 22 weeks after the drug induction. Crohn’s disease patients with exclusive perineal lesions, pregnant women and patients with a body mass index higher than 30 were excluded. Clinical disease activity assessed by Crohn’s disease Activity Index, Harvey Bradshaw index and the partial Mayo score was recorded during a routine visit and serum CRP, fecal calprotectin and serum IFX and anti-infliximab antibodies levels were measured, regardless of the time of the previous drug injection (Elisa assay). Clinical remission was defined by a CDAI score < 150 or HBI< 5 for CD and a partial Mayo score < 3 for UC. Strong clinical remission was defined by both clinical remission and CRP < 5mg/L and deep remission by the presence of clinical remission, CRP < 5mg/L and fecal calprotectin < 250 µg/g. The results of biomarker and drug concentrations were blinded to those of clinical disease activity.

Results

Among the 71 patients (47 F, 70 % CD, 27 % with concomitant immunosuppressants) enrolled, 55 (77%) patients were in clinical remission, 44 (62%) patients in strong remission and 31 (43%) patients in deep remission. 40 (56%) patients had fecal calprotectin < 250 µg/g regardless the clinical activity. The mean (SD) IFX levels were significantly higher in patients in clinical remission than in those with active disease (17.3 µg/mL (4.9) vs 12.3 µg/mL (4.5) ; p=0.014). Whatever the selected therapeutic target, serum drug levels differed significantly (p=0.01 for strong remission and p<0.001 for deep remission and normal fecal calprotectin). Univariate analysis revealed that only the age was significantly associated with sc IFX levels above 20µg/mL (p=0.045). Conversely, sex, type or duration of IBD, previous anti-TNF and combotherapy were not associated with sc IFX serum drug concentration > 20µg/mL. reported The best cut off values according to the therapeutic target are reported in Table 1. serum sc IFX levels more than 20µg/mL were strongly associated with a deep remission (sensitivity : 0.91, specificity : 0.80, accuracy : 0.85).

Conclusion

Serum sc IFX levels are significantly higher in IBD patients who achieved clinical and/or biomarker remission. serum IFX levels ≥20µg/mL were associated with a deep remission and also with the normalization of fecal calprotectin with an overall accuracy of 0.85 for both.